Lighter with child resistant shielded sparkwheel ignition mechanism

ABSTRACT

A sparkwheel lighter with a child resistant flint-type ignition mechanism, which includes in addition to those items commonly found in sparkwheel lighters, a cylindrical sparkwheel supported on an axle for rotation in contact with the flint for producing sparks when the sparkwheel file is rotated with respect to the flint, so that force applied to the thumbwheels to rotate the sparkwheel causes the thumbwheels to tilt over the sparkwheel to prevent direct actuation thereof by a user&#39;s thumb.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a child resistant ignitionmechanism for a lighter that makes sparks by rotating a sparkwheelagainst a flint, and in particular to an ignition mechanism havingthumbwheels that shield the sparkwheel from direct actuation and requirelarge downward forces be applied by the user to operatively connect themto the sparkwheel.

[0003] 2. Description of the Related Art

[0004] Some prior art ignition mechanisms have thumbwheels which areseparated from the sparkwheel, requiring additional force in apredetermined direction to engage the thumbwheels with the sparkwheels.If properly designed, this increases the difficulty of creating ignitionsparks enough so that someone without the intellectual capacity toappreciate the danger of an open flame, cannot produce a flame.

[0005] Ignition mechanisms for gas lighters are disclosed in U.S. Pat.Nos. 5,547,370, 5,759,023, 5,868,561, 5,913,674, 5,971,749, 5,997,281,6,053,727, and 6,074,198. These systems comprise ignition mechanisms inwhich two faces, one of the thumbwheel and one of the sparkwheel, arepushed together while the thumbwheel is rotated. When enough force isapplied between the thumbwheel and sparkwheel, any rotation of thethumbwheel is coupled to the sparkwheel, which rubs against a flint togenerate a shower of sparks. If gas is released when the shower ofsparks is present, ignition takes place. Various thumbwheel andsparkwheel engagement mechanisms have been proposed. Further, a systemthat controls the rotation of a thumbwheel and the engagement of athumbwheel and a sparkwheel by an elastic member is disclosed in U.S.Pat. No. 5,104,313.

[0006] For about a decade U.S. Government regulations have required thatinexpensive cigarette lighters whether refillable or disposable, havefeatures that make the production of a flame difficult for smallchildren. Ideally, these lighters would be difficult to operate forsomeone without the intellectual capability to understand and appreciatethe danger of an open flame, but are easily operated by adults.Experience has shown that precocious children can occasionally produce aflame with intellectually challenging child resistant lighters,especially when the operation of the lighter is demonstrated to them ona daily basis by their parents, and when those lighters are thereaftercarelessly left where children can experiment with them endlessly.

[0007] To determine whether or not a particular lighter has sufficientresistance to operation by a child, objective tests utilizing surrogatelighters are used with children fifty one months old or younger toassure that very few children in that age group can operate thesurrogate lighter in a fashion that would produce a flame in theequivalent lighter being sold in the United States. Since theintellectual capability of all children in the target age group is avery difficult characteristic to design against, in fact, childresistant lighters in the United States tend to be a combine trickinessof operation and difficulty of operation by someone who has limitedmanual dexterity, limited strength, and/or small hands and fingers.

[0008] There are places in the world that are progressing fromsubsistence farming economies, where simple items, such as cigarettelighters, can be assembled at extremely low cost by hand. Such low laborcosts enable a manufactured cost that is about half of the cost that canbe achieved by automation in industrialized countries with higher laborcosts. Therefore, it has become critical to those selling lighters inthe United States to design child resistant lighters, which can bemanufactured very economically, by hand.

[0009] Summarizing, a particular lighter design must be economical tomanufacture and child resistant. Yet, it must be manufacturable inprototype quantities and tested prior to importation as a productionmodel into the United States. This process takes somewhere between sixmonths and a year. Therefore, many individuals and companies have filedpatent applications, some with relatively broad claims, prior to thetime that they have determined that the child resistancy of the lighterbeing patented is sufficient to pass U.S. Government regulations. Now,if someone wishes to improve one or more aspects of a lighter, not onlymust the lighter be designed for extremely economical manufacture, itmust avoid the claims of patents on lighters, which although notsufficiently child resistant to be allowed into the United States,cannot be improved by others to provide the required child resistancy,because of the broad claims in of one or more unexpired patents.

[0010] Examples include Zellweger, U.S. Pat. No. 5,096,414, whereinchild resistancy is provided by disconnected thumbwheels on either sideof the sparkwheel of a sparkwheel lighter. The patent indicates that anadult thumb has enough flesh to operate the sparkwheel directly, whereasa child's thumb does not, even though presumably a child's thumb isthinner and might fit between the two thumbwheels if stroked front toback rather than across the thumbwheels. Lighters, whose primaryactuation method is a force sensitive slipable mechanism between thesparkwheel and the thumbwheels such as those shown in U.S. Pat. No.5,547,370 which employs a polygonal thumbwheel slip mechanism have beenenjoined from sales in the Unites States by the owner of the Zellwegerpatent because it is possible for the flesh of an adult thumb toactually contact and assist in the rotation of the sparkwheel.

[0011] Therefore, there has been a need to provide a non-infringingspark wheel lighter, which can be economically manufactured andassembled essentially by hand and at the same time provide the requiredchild resistancy.

SUMMARY OF THE INVENTION

[0012] The present ignition mechanism for a gas lighter solves theaforementioned problems and makes sparks when a sparkwheel is rotatedagainst a flint. The present ignition mechanism includes two axlesupport members mounted to the body of the lighter between which an axleextends. A sparkwheel and two inwardly flanged thumbwheels are looselymounted on the axle, the sparkwheel is loosely mounted for ease ofmanual assembly while the thumbwheels are loosely mounted to providechild resistancy, as will be explained. The axle support members retainstub portions of the axle in bearings so that the axle rotates about afixed line with respect to the flint. Therefore to cause the sparkwheelto rotate with respect to the flint to produce sparks, requires that theaxle be turned. The cross-sectional shape of the axle where thesparkwheel in mounted thereon, only needs to be shaped with respect to ahole through the sparkwheel so that relative rotational motion is notpossible. This can also be accomplished by pinning or keying the axleand sparkwheel together or through the use of adhesive, although theformer increases cost and the latter may produce a failure point thatmakes the lighter inoperative.

[0013] The axle shape where the thumbwheels are mounted is preferablyrotationally non-round symmetrical, with a polygon shape beingpreferred. The thumbwheels have center holes that are complementary tothe axle cross-sectional shape, but of a size large enough to turn withrespect thereto, even when the thumbwheels are tilted with respect tothe axis of the axle. The inward flange on each thumbwheel forms thethumb engagement outer circumferential surface therefor. For the user toengage the thumbwheels with the axle, a substantial inward radial forcemust be applied between the user's thumb and the flange. Since theengagement force between the thumbwheels and the axle acts a distancespaced from the sparkwheel and outside the thumb force applied to theflange, the thumbwheels tilt toward each other, over the sparkwheel,preventing the thumb from engaging the sparkwheel to allow directrotation thereof. Children of an age where they do not appreciate thedanger of fire, have difficulty producing enough radially inward forceto engage the thumbwheels with the axle, and at the same time producingthe circumferential force required to rotate the axle and sparkwheel toproduce gas igniting sparks. This difficulty of operation is partlybecause the thumbwheels easily turn with respect to the axle, so theaction necessary to engage the thumbwheels with the axle is not obviousto the child, and partly because children are unlikely to have enoughstrength to accomplish spark production.

[0014] The complementary shapes of the axle and thumbwheels can bechanged both in relative size and shape and the clearance can be changedto allow more or less tilting of the thumbwheels. In addition, thestrength of the flint springs can be changed to produce a balance wheremost adults can operate the lighter, but few, if any, children under theage of fifty one months can operate it even if parents carelesslydemonstrate proper operation and leave multiple examples where a childcan experiment with the lighter many times.

[0015] The gas igniting sparks are produced in the vicinity of the gasrelease nozzle. The gas is released when the nozzle is lifted by arocking gas release lever. The construction of nozzles is such that itis preferable that they are lifted in a straight line, but the morenormal pivoting gas release lever tries to move the nozzle along acircular path. Therefore, the present lever is formed with a pair ofcentrally positioned rockers which rock and slide on suitable surfaceson the top of the lighter body so the nozzle can move in a linear pathwith the lever moving end to end to compensate for the angulardifferences between the nozzle and the gas release lever as it isoperated.

[0016] Therefore, an object of the present invention is to provide achild resistant ignition system which is versatile so that it can passchild resistancy testing in many countries.

[0017] Another object is to provide a child resistant ignition systemthat can be assembled in an automated factory, a partly automatedfactory or manually, so that it can be produced at competitive prices,no matter how the costs of labor vary throughout the world.

[0018] Another object is to provide a child resistant ignition systemthat avoids infringement of U.S. patents broadly claiming childresistant features, even if those claimed features may not pass childresistance testing in the United States.

[0019] Another object is to provide a child resistant ignition systemwhich is easily operated by those with the intellectual capacity toappreciate the danger of an open flame.

[0020] These and other objects and advantages of the present inventionwill become apparent to those skilled in the art after considering thefollowing detailed specification, together with the accompanyingdrawings wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

[0021]FIG. 1 is a partial cross-sectional side elevational view of a gaslighter having the ignition mechanism of the present invention in thenon-operating state;

[0022]FIG. 2 is a detail cross-sectional side view of the sparkwheel, aflint with its spring mounted on a polygonal axle and also showing oneof the thurnbwheels of the lighter of FIG. 1;

[0023]FIG. 3 is a partial cross-sectional front view of the sparkignition assembly for the lighter of FIG. 1 as it is being actuated by athumb;

[0024]FIG. 4 is a detail cross-sectional side view of a thumbwheelmounted on the polygonal axle of the lighter of FIG. 1;

[0025]FIG. 5 is a detail cross-sectional side view of a modifiedthumbwheel mounted on the polygonal axle of the lighter of FIG. 1;

[0026]FIG. 6 is an enlarged cross-sectional view of the thumbwheel forloose mounting on the polygonal axle of the lighter of FIG. 1;

[0027]FIG. 7 is a side detail view of the gas release lever and gasrelease nozzle of the lighter of FIG. 1; and

[0028]FIG. 8 is a motion diagram of the gas release lever of FIG. 1showing its rocking and sliding movement.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0029] The following is a description explaining in detail preferredembodiments of the ignition mechanism according to the presentinvention. Referring to the drawings more particularly by referencenumbers, the gas lighter 10 is equipped with a body 12 in which fuel gasis stored, and a nozzle 14, through which fuel gas is released by therocking of an operating lever 16. The operating lever 16 includes oneend 18 that engages the nozzle 14, lifting it to release the gas whenthe opposite end 20 is depressed by the user's thumb. The gas is ignitedby a shower of sparks generated by a child resistant ignition assembly22.

[0030] As shown in FIG. 2, the assembly 22 includes a flint 24, which ispushed upward against a sparkwheel 26 by a spring 28. The sparkwheel 26has the configuration of a cylindrical file. Preferably, the sparkwheel26 includes a non-round opening 30 there through so that it can bemanually slid onto and thereby mounted on a non-round axle portion 32 ofan axle 34, shown as having a sextuple polygonal cross-sectional shapeover most of its length. The axle 34 includes short round stubs 36extending from the non-round portion 32 which are supported in bearingholes 38 formed in axle support members 40 and 41 extending upwardlyfrom the body 12 of the lighter 10. Therefore, the sparkwheel 26 andaxle 34 rotate together.

[0031] As shown in FIGS. 3 and 4, two thumbwheels 42 and 44 are alsomounted on the non-round portion 32 of the axle 34 with a matchingnon-round hole, such as the sextuple polygon hole 46 which is congruentto the axle portion 32, but large enough to rotate there about unlessenough downward force is applied to the thumbwheels 42 and 44 to causethem to engage the axle portion 32. If at the same time radial force isapplied to the thumbwheels 42 and 44, the axle 34 and sparkwheel 26rotate therewith to produce a shower of sparks.

[0032] As shown in FIG. 5, the thumbwheels 42 or 44 can include a hole48 that is generally polygonal shaped with relieved corners 50 so theforce required to engage the thumbwheels 42 or 44 with the axle 34 isrelatively uniform as the assembly 22 rotates. The relieved corners 50,shown with the modified thumbwheel 52, also assist in allowing inwardfacing flanges 54 and 56 (FIG. 6) at the outer peripheries 58 and 60 ofthe thumbwheels 42 and 44 to lean inwardly in response to force (arrow62) applied by the user's thumb 64 thereto. If the thumbwheels 42 and 44did not tilt, the distance between the thumbwheels 42 and 44 could notbe reduced below the diameter of the flint 24. The tilting or leaningcauses the flanges 54 and 56 to guard the sparkwheel 26 from beingdirectly actuated by a thumb 64. The distance 66 between the axlesupport members 40 and 41 between which the axle portion 32 extends, islarger than the width 67 of the sparkwheel 26 and the width 68 of diskportions 69 and 70 of the thumbwheels 42 and 44. This provides clearancefor the tilt caused because the average force (arrow 72 of FIG. 6)initially applied by the thumb 64 is inside the average reactive force(arrow 76) by enough distance (arrow 78) between the thumbwheel hole 48and the axle portion 34 to cause tilting to reliability to occurwhenever an ignition is attempted.

[0033] Therefore, ignition sparks are very difficult for a child toproduce because not only must the child recognize that downward forcemust be applied to operatively engage the thumbwheels 42 and 44 with thesparkwheel 26, the child must develop relatively large forces bothinwardly and radially. Then the child must release gas by depressing theoperating lever 16 before the sparks extinguish.

[0034] The nozzle 14 is designed for a linear pull to release gas.Therefore, a conventional pivoted lever whose ends follow circular pathstend to stress the nozzle 14. In the present lighter 10, instead ofbeing restrained to pivot, the operating lever 16 includes a centersection 80 as shown in FIG. 7 including a pair of rockers 82 and 83,which engage a top surface 84 of the body 12. An optional leverextension 85 can be provided which is loosely restrained in a cavity 86in the lighter body 12 to stabilize the lever 16 from movement toward oraway from the nozzle 14. With a rocker type operating lever 16, themotion of the nozzle 14 can be straight vertically 88 as shown in FIG.8, which is a motion diagram of the lever 16. Note that the end 20follows a curved path 90 and the center section 80 slides 92 when itrotates 94.

[0035] Thus there has been shown and described novel child resistantignition systems for sparkwheel lighters, which fulfill all the objectsand advantages sought therefor. Many changes, modifications, alterationsand other uses and applications which do not depart from the spirit andscope of the invention are deemed to be covered by the invention whichis limited only by the claims that follow:

1. A lighter with a child resistant spark producing system including: alighter body; a flint supported by said lighter body; an axle supportedby said lighter body, said axle having: at least one non-roundcross-section portion having: a maximum diameter; a sparkwheel supportedfor rotation with said axle in contact with said flint for producingsparks when said sparkwheel and axle are rotated with respect to saidflint; a first thumbwheel mounted on said axle adjacent said sparkwheelfor rotation with respect to said axle and said sparkwheel; and a secondthumbwheel mounted on said axle adjacent said sparkwheel opposite saidfirst thumbwheel having: a peripheral flange extending inwardly towardsaid sparkwheel and spaced radially therefrom, said peripheral flangeforming: a thumb contact outer ring surface having: a center ringsurface portion; a non-round bearing surface having: a center bearingportion positioned laterally further from said sparkwheel than saidcenter ring portion; and a minimum diameter about said non-roundcross-section portion, said minimum diameter being larger than saidmaximum diameter, whereby thumb force applied to said thumb contactouter ring causes said second thumbwheel to tilt with respect to saidaxle so that said peripheral flange covers a portion of said sparkwheelto prevent direct actuation of said sparkwheel by a user.
 2. The lighteras defined in claim 1 wherein said sparkwheel is supported on said axlefor sliding there along.
 3. The lighter as defined in claim 1 whereinsaid first thumbwheel includes: a peripheral flange extending inwardlytoward said sparkwheel and radially spaced therefrom, said peripheralflange forming: a thumb contact outer ring surface having: a center ringsurface portion; a non-round bearing surface having: a center bearingportion positioned laterally further from said sparkwheel than saidcenter ring portion; and a minimum diameter positioned about saidnon-round cross-section portion, said minimum diameter being larger thansaid maximum diameter, whereby thumb force applied to said thumb contactouter rings causes said first and second thumbwheels to tilt toward eachother with respect to said axle so that said peripheral flanges coverportions of said sparkwheel to restrict direct actuation of saidsparkwheel.
 4. The lighter as defined in claim 3 wherein said axle has:outer axle portions for rotationally engaging said body portion; and acentral axle portion of a first length, and wherein said sparkwheel andsaid non-round bearing surfaces have an assembled minimum width that isless than said first length.
 5. The lighter as defined in claim 3wherein said flint has: a flint diameter, and wherein when said firstand second thumbwheels tilt toward each other with respect to said axle,a minimum gap there between is established that is less than said flintdiameter.
 6. The lighter as defined in claim 1 wherein said axle has:outer axle portions for rotationally engaging said body portion; and acentral axle portion of polygonal cross-section.
 7. The lighter asdefined in claim 6 wherein said central axle portion of polygonalcross-section has: a plurality of flat portions, and wherein saidnon-round bearing surface includes: an identical number of flat portionsas said central axle portion.
 8. A lighter with a child resistant sparkproducing system including: a lighter body; a flint supported by saidlighter body; an axle supported by said lighter body, said axle having:a non-round cross-section portion having: a maximum diameter; acylindrical file supported on said axle for rotation concentricallytherewith in contact with said flint for producing sparks when saidcylindrical file is moved with respect to said flint; a first thumbwheelmounted on said axle adjacent said cylindrical file so that said firstthumbwheel can rotate with respect to said axle and said cylindricalfile; and a second thumbwheel mounted on said axle adjacent saidcylindrical file so that said second thumbwheel can rotate with respectto said axle and said cylindrical file, said second thumbwheel beingmounted opposite said first thumbwheel, said first and secondthumbwheels each having: a peripheral flange extending inwardly towardsaid cylindrical file and radially spaced therefrom, said peripheralflange forming: a thumb contact outer ring surface having: a center ringsurface portion; a non-round bearing surface having: a center bearingportion positioned laterally further from said cylindrical file thansaid center ring portion; and a minimum diameter about said non-roundcross-section, said minimum diameter being larger than said maximumdiameter.
 9. The lighter as defined in claim 8 wherein said cylindricalfile is supported on said axle for sliding there along.
 10. The lighteras defined in claim 8 wherein said flint has: a flint diameter, andwherein when said first and second thumbwheels tilt toward each otherwith respect to said axle, a minimum gap there between is establishedthat is less than said flint diameter.
 11. The lighter as defined inclaim 8 wherein said axle has: outer axle portions for rotationallyengaging said body portion; and a central axle portion of polygonalcross-section.
 12. The lighter as defined in claim 11 wherein saidcentral axle portion of polygonal cross-section has: a plurality of flatportions, and wherein each of said non-round bearing surfaces of saidfirst and second thumbwheels include: an identical number of flatportions as said central axle portion.
 13. The lighter as defined inclaim 11 wherein said cylindrical file includes: a polygonal orificewhich slides on said central axle portion of polygonal cross-section.14. The lighter as defined in claim 11 wherein said central axle portionof polygonal cross-section has: a plurality of flat portions, andwherein said non-round bearing surfaces of said thumbwheels eachinclude: a polygonal orifice of a shape similar to said central axleportion of polygonal cross-section.
 15. A lighter with a child resistantspark producing system including: a lighter body; a flint supported bysaid lighter body; an axle supported by said lighter body for rotationwith respect to said flint a sparkwheel supported on said axle forrotation against said flint, said sparkwheel being positioned forcontact with said flint for producing sparks when said sparkwheel isrotated with respect to said flint, said sparkwheel having: a maximumdiameter; first and second thumbwheels loosely mounted on said axle,said first and second thumbwheels each having: a supporting disk having:a central orifice mounted on said axle; a cylindrical flange extendinginwardly from said supporting disk having: a minimum diameter largerthan said maximum diameter of said sparkwheel; and a peripheral outersurface, whereby said peripheral outer surfaces of said thumbwheels aregenerally inward of said central orifices so that when force is appliedto said peripheral outer surfaces, said thumbwheels lean over saidsparkwheel to reduce any direct contact that might occur between an userand said sparkwheel.
 16. The lighter as defined in claim 15 wherein saidflint has: a flint diameter, and wherein when said first and secondthumbwheels tilt toward each other with respect to said axle, a minimumgap there between is established, which is less than said flintdiameter.
 17. The lighter as defined in claim 15 further including: axlesupport members extending from said lighter body spaced a distancegreater that the total width of said sparkwheel and said supportingdisks, whereby said axle support members allow said thumbwheels to tiltinwardly over said sparkwheel.
 18. The lighter as defined in claim 17wherein said axle includes: a polygonal central axle portion having: aplurality of flat portions, and wherein said supporting disks of saidfirst and second thumbwheels include: non-round bearing surfaces with:an identical number of flat portions as said central axle portion. 19.The lighter as defined in claim 17 wherein said flint has: a diameter,and wherein said sparkwheel includes: a width at least as large saidflint diameter.
 20. The lighter as defined in claim 15 wherein said axlehas: a length wider than the total width of said sparkwheel and saidthumbwheels.
 21. A method of providing child resistance to a spark wheellighter including: loosely mounting inwardly extending,circumferentially flanged drive wheels adjacent the sides of thesparkwheel so that downward radial force thereon required to produce aspark: causes the flanges to tilt over the sparkwheel; and preventsdirect actuation of the sparkwheel by a user's digit.